Virtual Network Computing

Have you ever found yourself away from home, wishing you had your desktop machine with you? Have you ever wished you could show someone, remotely, how to do something instead of talking them through it over the phone? These things and much more can be done with a nifty little freeware utility called Virtual Network Computing, or VNC.

    What VNC does is this: it enables a remote user (who knows the password) to take control of your machine via the internet. They can view files, run programs, delete stuff, etc. -- in other words, they can use your computer exactly as if they were sitting in front of it, although a bit slower. This might sound a little frightening, and it is, except that you have a good deal of control over the situation. You set the password, you can kick them out if they abuse it, and you have to be online already & have VNC Server running for anyone to access your machine. In reality, you’ll usually be setting up sessions specifically, or acting as the remote user yourself.

    Another nifty thing you can do with VNC is letting someone else watch your screen, but disabling their control over your computer. This is great for showing your newbie friends how to do things -- get them logged on, and do it while they watch. It’s a lot easier than explaining it over the phone. The best part about this is that they don’t need anything special -- just a Java-capable web browser.

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Ultra Wide Band

UWB is a wireless technology that transmits binary data—the 0s and 1s that are the digital building blocks of modern information systems. It uses low-energy and extremely short duration (in the order of pico seconds) impulses or bursts of RF (radio frequency) energy over a wide spectrum of frequencies, to transmit data over short to medium distances, say about 15—100 m. It doesn’t use carrier wave to transmit data.

UWB is fundamentally different from existing radio frequency technology. For radios today, picture a guy watering his lawn with a garden hose and moving the hose up and down in a smooth vertical motion. You can see a continuous stream of water in an undulating wave. Nearly all radios, cell phones, wireless LANs and so on are like that: a continuous signal that's overlaid with information by using one of several modulation techniques.

Now picture the same guy watering his lawn with a swiveling sprinkler that shoots many, fast, short pulses of water. That's typically what UWB is like: millions of very short, very fast, precisely timed bursts or pulses of energy, measured in nanoseconds and covering a very wide area. By varying the pulse timing according to a complex code, a pulse can represent either a zero or a one: the basis of digital communications.

Wireless technologies such as 802.11b and short-range Bluetooth radios eventually could be replaced by UWB products that would have a throughput capacity 1,000 times greater than 802.11b (11M bit/sec). Those numbers mean UWB systems have the potential to support many more users, at much higher speeds and lower costs, than current wireless LAN systems. Current UWB devices can transmit data up to 100 Mbps, compared to the 1 Mbps of Bluetooth and the 11 Mbps of 802.11b. Best of all, it costs a fraction of current technologies like Blue-tooth, WLANs and Wi-Fi.

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Ubiquitous Networking

Mobile computing devices have changed the way we look at computing. Laptops and personal digital assistants (PDAs) have unchained us from our desktop computers. A group of researchers at AT&T Laboratories Cambridge are preparing to put a new spin on mobile computing. In addition to taking the hardware with you, they are designing a ubiquitous networking system that allows your program applications to follow you wherever you go.

    By using a small radio transmitter and a building full of special sensors, your desktop can be anywhere you are, not just at your workstation. At the press of a button, the computer closest to you in any room becomes your computer for as long as you need it. In addition to computers, the Cambridge researchers have designed the system to work for other devices, including phones and digital cameras. As we move closer to intelligent computers, they may begin to follow our every move.

    The essence of mobile computing is that a user’s applications are available, in a suitably adapted form, wherever that user goes. Within a richly equipped networked environment such as a modern office the user need not carry any equipment around; the user-interfaces of the applications themselves can follow the user as they move, using the equipment and networking resources available. We call these applications Follow-me applications.

    Typically, a context-aware application needs to know the location of users and equipment, and the capabilities of the equipment and networking infrastructure. In this paper we describe a sensor-driven, or sentient, computing platform that collects environmental data, and presents that data in  a form suitable for context-aware applications.

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